1. Field of the Invention
The present invention relates generally to electron beam apparatus, and more particularly with immersion electrostatic lenses in electron beam apparatus.
2. Description of the Background Art
Electron beam instruments are utilized for various purposes, including inspection, review and metrology of substrates in semiconductor manufacturing. Electron beam instruments typically include, among other components, an electron gun or source, condenser lenses, beam deflectors and an objective lens.
The objective lens is configured to focus the incident electron beam onto the substrate being examined. Objective lenses may utilize magnetic or electrostatic means to focus the incident beam. Some objective lenses are immersion lenses which are configured close to the substrate surface and have short focal distances.